Cutting-tool.



No. 865,918. PATENTBD SEPT. 10, 1907. E.V W. LADD. CUTTING TOOL.

APPLICATION FILED JAN. 2B. 1907.

narran srnrgns PATENT orrron.

EARNESI W. LADD, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR OF ONE-FOURTH TO HUNTER ARNOLD, ONE-EIGHTH TO WILLIAM H. ROHRER, ONE-EIGIITH TO HARRY L. WI-IEATLEY, AND ONE-EIGHTH TO B. M. MCQUINN, ALL OF WASHINGTON, DISTRICT OF COLUMBIA, AND ONE-EIGI'ITH TO THOMAS J. FARRAR, OF VIRGINIA. y

4 No. 865,918. l Specification of Letters Patent. Patented Sept. 10, 1907.

Continuation of application Serial No. 321,416, filed June 12, 1906. This application filed January 28, 1907. Serial No. 354,535.

To all whom it may concern: A further' object isto provide for positive and abso- Be it known that I, laitnirs'r W. LADD, a citizen of lute adjustability of the aforesaid twisting and tensionthe United States, residing at Washington, in District ing means, tliuscompensating for all wear of the mov- 55 of Columbia, have invented certain new and useful i ing contacting, parts, andfrendering such adjustable Y 5 Improvements in Cuttingflools, and I do hereby demeans readily detachable and'replaceable.

clarethefollowing to bea full, clear, and exact de- A further object is to provide a tool of this type scription of the invention, such as will enable others wherein the blades are self sharpening; a tool which skilled in the art to which it appertains to make and use cannot become deranged or get out of orde-r owing to its the saine. simplicity of construction; and one which is extremely IO My invention relates to cutting tools of the type emeconomical of manufacture.

ployin'g a pair of pivotally connected and coperating With these and other objects in view, tliis'linvention blades, has particular reference to scissors and shears, comprises the novel features of construction and combiand is a continuation of my former application Serial nation of parts more fully hereinafter described. V65 No. 321,416. 4In the operation of tools of this type now In the accompanying drawings which form part of l5 in general use,`there is a well known tendency on the this application: Figure I, represents in plan view a part of the blades to spread or spring apart thus seriously pair of closed shears embodying my invention. Fig. detracting from the proper cooperation of their cutting 2, is 'a fragmentary view showing a longitudinal section edges in effecting a clean, sharp cut, with a consequent of the invention taken on the line 2;-2 of Fig, l. Fig. 70 detraction from the efiiciency of the tool. Attempts l `3, is a' detail transverse section taken on the line 33'of have been made to overcome this defect, notably by Fig. I. Fig. 4, is a perspective view, partly in section, forming one or both of the blades, during the course of and partly broken away, showing the shears' partially manufacture, with a protuberance or` a pair of proopen. Fig. 5, is a detail plan view of the rear portion l'uberances or heels, disposed in rear of the lulcrum of of one of the blades. i "9., 75

the blades, and adapted, during the cutting operation Reference being hadrto the drawings, it will be seen to throw the forward, active portions thereof together that the present tool comprises a pair of pivotally conin parallel lines. This mode of construction is, hownected cutting blades I and 2 fulcrumed between their over, rendered objectionable by the fact that such proends for relative movement upon the pivoting member tuberances or heels must necessarily be finished by or screw 3 and having at their rearends handles or bows 80 hand, thus increasing the cost of manufacture, and, 4 of usual form, the forwardv active portions of the blades 3() moreover, such protuberances rapidly wear away, in being provided with coperating sharpened cutting practice, thus becoming ineffective for their intended edges 5. The foregoing parts of the tool are of usual purpose. Various other means have heretofore been well known construction and material, and, except in devised for the alleged purpose of overcoming the ob the particulars hereinafter explained, are adapted in 85 jcction in question, but such devices have invariably practice to perform their ordinary functions, n

met with disfavor owing to their impracticability and In accordance with my invention there is tapped high cost of production. 1l centrally through the blade I at a point in rear of the This invention has for its obiect to provide a simple, pivoting screw 3 a combined twisting and tensioning inexpensive and efficient means for imparting to the member or screw 6, which latter is accordingly adjustblades of scissors, shears and similar tools, a relative able with relation to said blade, and is by preference of l 0 twisting action during the operation of cutting, whereuniform size throughout its length, thus providing for, by the shearing edges are automatically caused to apand permitting a comparatively extensive range of adproach each other with gradually increasing force, and justment, or its ready removal if occasion should arise are thus maintained in proper coperative relation to withdraw and replace same. The inner end of said throughout their entire length. twisting and tensioning member 6, as shown, bears 45 A further object of the present invention, is to effect upon the inner face of the adjacent portion of blade 2 a proper tensioning ofthe active portions of said blades, and there presents an extended bearing surface toward and to provide means whereby such tension will be ausaid blade, with which, owing to its preferred location, tomatically and gradually increased toward the outer it is at all times in Contact; thus, insuring certainty of ends or points thereof, as the cutting operation proaction, and compensating for wear of the parts, as more 5() gresses; thus insuring proper coperation of the blades fully hereinafter explained.

even to their extreme points for effecting a clean It will be noted that screw 6 riding over the inner smooth ej-ut. u Y n A Y A Y face of blade 2, during the operation of cutting, causesa @L v.. s

relative tilting or twisting of the blades transversely to their direction of length; and, in addition a tilting of the blades longitudinally.

The operation is as follows: In practice, the handles lf are grasped and the tool manipulated as usual. screw (i, adjustable with relation to blade l, rides over the inner face of blade 2 causing a relative twisting oi said blades transversely as indicated by the arrows a in Fig. 4, and as a consequence the cutting edges 5 oi said blades are brought into contact with gradually increasing force as the cutting operation progresses, and as said screw 6 approaches its resting place in the longitudinal center of blade 2. Simultaneously with said action, screw G in its passage over the inner face of blade 2 as aforesaid, also slightly spreads the blades in rear of their pivotal point as indicated by the arrows o in Fig. 2, thus tensioning or throwing their forward active portions toward each other for maintaining them in proper cooperative relation. It will be apparent also that the blades will thus be maintained under the proper and appropriate tension throughout their entire length as the cutting progresses, and further that the screw G may readily be adjusted to vary the tension according to the nature of the material acted upon.

ln tools of the type under consideration, and particularly in shears of unusual length, there is a marked tendency of the blades to spring apart as the cutting progresses toward their outer ends or points, thus rendering the tools more or less defective in action. ln order to more effectually overcome this defect, I provide on the inner face of blade 2 at an appropriate point in rear of the pivot 3, a transversely inclined bearing surface 7 over which the inner end of screw 6 rides and which gradually increases in elevation from the outer rear edge of blade 2 toward its longitudinal center. Thus it is apparent that as the blades are moved to closed position, screw 6 riding over said inclined sin'- face 7 the more effectually produces the before mentioned transverse relative twisting of said blades and in addition the longitudinal tensioning thereof; also that both of said results are not only automatic and simultaneous in their action, but are applied with gradually increasing force, and combine to insure proper coperation of the blades throughout the entire length thereof for effecting smooth, clean cutting of the material acted upon. It will be noted also that blades formed and assembled as hereinbefore described do not require the nicety of initial adjustment at hands of the manufacturer which is necessarily given tools of this type ordinarily, moreover the cost of manufacture is otherwise reduced as compared with the ordinary tools of like character and size. For example the grinding of the blades is greatly facilitated by overcoming the necessity of hand finishing at the hilts or heels, since in carrying out my invention it is unnecessary to produce upon the inner surface of blade 2 a clearly defined incline 7 as shown, but the full mechanical equivalent thereof may be formed with ease and facility by a slight twist of the blade at its hilt during the process of grinding.

Having thus described my invention what I claim is:

l. In a cutting tool, the combination with a pair oi' pivotally connected blades, of separable means secured to one of said blades for imparting thereto a transversely twisting action with relation to the other of said blades, substantially as described.

2. In a cuttingl tool, the combination with a pair of pivotally connected blades, ot' means adjustable with relation to one of said blades t'or imparting thereto a transversely twisting action with relation to the other of said blades, substantially as described.

In a cutting' tool, the combination with a pair oi' pivotally connected blades, of means adjustable with relation to one ot' said blades for impartingl thereto a trans versely twistingl and tensioning action with relation to the other of said blades, substantially as described.

4. In a cutting tool, the combination with a pair ot pivotally connected blades, of means adjustable with relation to one of said blades located in rear of the pivotal point for imparting a transverselyv twisting action to said blades, substantially as described.

5. In :i cutting' tool, .the combination with a pair of pivotally connectedblades, of means carried by one oi said blades and adjustable with relation thereto for imparting a transversely twisting action to said blades, substantially as described.

G. In a cutting tool, the combination with a pair ot pivotally connected blades, of an adjustable tensioning member' interposed between said blades adapted to impart a transversely twisting action thereto, substantially as described.

T. In a cutting tool, the combination with a pair of pivotally connected blades, ot' an adjustable tensioning member threaded through one of said blades and bearing upon the other of said blades for imparting a transversely twisting action thereto, substantially as described.

S. In a cutting tool, the combination with a pair of pivotaily connected blades, of an incline upon one of said blades` and an adjustable tensioning member carried by the other of said blades adapted to traverse the incline aforesaid for imparting to the blades a transversely twistinf;l action, substantially as described.

S). In a cuttingtool, the combination with a pair ot pivotally connected blades, of an incline upon one of said blades in rear of its pivotal point, and an adjustable tensioningl member carried by the other of said blades adapted to traverse the incline aforesaid for imparting to the blades a transversely twisting action, substantially as described.

10. In a tool ot' the type described. a pair of crossed pivoted blades havingl sharpened inner edges, one of said blades being provided on its inner t'ace and in rear of its tulcruin with a transversely disposed inclined bearing face, and a rigid unyielding tensioning member carried by the other blade to ride on said bearing face for throwing the outer ends of the blades, together, said tensioning member being adjustable to compensate for wear.

In testimony whereof I affix my signature, in presence of two subscribing witnesses.

EARNEST W'. LADI). 

